Effect of kidney transplantation on sexual dysfunction in patients with end stage renal disease: A systematic review

End-stage renal disease (ESRD) is associated with a multitude of physical, psychological, and social health challenges, including a profound impact on sexual and reproductive health. Among males with ESRD, erectile dysfunction (ED) is highly prevalent due to factors such as underlying comorbidities, including diabetes and hypertension, and the physiological effects of long-term dialysis. Kidney transplantation (KTx) has been proposed as a potential intervention to mitigate the effects of ED by restoring renal function and improving hormonal balance. However, the evidence surrounding the effectiveness of KTx in improving sexual function, specifically erectile function (EF), remains inconclusive. This systematic review and meta-analysis aim to evaluate the effects of KTx on sexual dysfunction (SexDys), particularly ED, in male ESRD patients. To evaluate the benefits and potential harms of KTx compared to other forms of renal replacement therapy in improving EF in adult males with ESRD, assessed using the international index of EF (IIEF), to survey the prevalence of SexDys in this population, and to assess the correlation between various factors and SexDys through regression analysis. A systematic search of PubMed, EMBASE, Cochrane Library, Scopus, ClinicalTrials.gov, and Google Scholar was conducted, following the PRISMA 2020 guidelines. Prospective and retrospective cohort studies, as well as cross-sectional studies assessing EF pre- and post-transplantation, were included. These studies used validated tools such as the IIEF to measure EF. Meta-analyses were performed using a random-effects model to estimate standardized mean differences (SMD) and hazard ratios (HR) with 95% confidence intervals (CI). Heterogeneity was assessed using the I² statistic, and publication bias was evaluated with a funnel plot and the Egger's test. A total of 2419 studies were identified, with 362 abstracts screened and 193 full-text articles reviewed. Ultimately, 11 studies were included for qualitative analysis and 7 for quantitative synthesis. The random effects model for SMD yielded a combined estimate of 0.43 (95%CI: -0.20-1.07), indicating a small but non-significant improvement in EF post-transplantation. The heterogeneity across studies was substantial (I² = 90%), reflecting significant variability in outcomes. Subgroup analysis showed greater improvements in EF among living-donor transplant recipients compared to those receiving organs from deceased donors. Despite this trend, the overall result for changes in EF was not statistically significant (P = 0.15). Additionally, the combined HR from the meta-analysis was 2.87 (95%CI: 1.76-4.69), suggesting that KTx significantly increases the likelihood of improved EF, though variability between studies persisted (I² = 63%). While KTx offers some promise for improving EF in male ESRD patients, the overall evidence remains inconclusive due to high heterogeneity between studies and a lack of statistical significance in the combined results. Despite this, individual studies suggest that KTx may lead to significant improvements in EF for certain subgroups, particularly living-donor recipients. Future research should focus on larger, well-designed cohort studies with standardized outcome measures to provide more definitive conclusions. Addressing SexDys as part of routine care for ESRD patients undergoing KTx is crucial to improving their overall quality of life. However, adjunct therapies such as phosphodiesterase type 5 inhibitors may be necessary for those who do not experience adequate improvements post-transplantation.